In devices which have charged particle beams or electron beams, such as electron microscopes, ion microscopes, free electron lasers, particle accelerators and other high energy heavy ion applications, there is a demand for lenses to focus the beams, with a high degree of accuracy,
The use of dipoles, quadrupoles, sextupoles and higher order pole arrangements are common for deflecting the path of charged particle beams.
The poles employed in the prior art have a variety of shapes and sizes for varying the flux lines of the magnetic or electric fields.
Many devices use a series of lens along the beam path to try to focus the charged particle beams.
However conventional magnetic optics have not been practically demonstrated where sextupoles, octupoles or higher order poles have been used.
The poles used to deflect the charged particle beams may be electrostatic or magnetic.
Some devices use permanent magnets which may have distance adjusting means to move the magnet relative to the charged particle beam. Other devices use electromagnets with variable intensity capability. The electrostatic devices use charged plates to influence the charged particle beams.
In all the devices precision of alignment of the fields of force is critical. Most beams deflecting devices are large and have a relatively small number of poles.
Very fine adjustments for focusing charged particle beams with many closely spaced adjustable magnitude poles are not possible with the devices found in the prior art.